R J Cano on Thu, 31 Jan 2013 09:25:50 +0100


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Happy capicua day !!



Greetings,

Original message in the attachment file.

Cheers,

R. J. Cano

P.S.: "Just once in a lifetime".

/*
 *
 * Written by R.J. Cano Jan 31 2013
 *
 * The palindromic day: ... 31 2013
 * ........................ 31?2013
 * ........................ 3102013
 * ...................................
 * ................................... Let be r a radix, Let's set r=10 for the Decimal system;
 * ...................................
 * ................................... Truncate 3 digits from right: 3102{013} ---> 3102
 * ................................... Truncate 3 digits from left:  {310}2013 ---> 2013
 * ...................................
 * ........................................ Subtract:             -------------------------
 * ........................................ Divide by (r-1):                   ---> 1089
 * ........................................ Again a palindromic:               --->  121
 * ........................................ It is a perfect square:            ---> 11^2
 * ........................................
 * ........................................ It is written with the same digits!!
 * ........................................ Either as it is or as a perfect square ---> 121, 11^2;
 * ........................................
 * ........................................ It is the product of two primes: ---> 121= 11*11
 * ........................................
 * ........................................ (1+2+1)^(1*2*1)= (1*2*1)^(1+2+1)
 * ........................................
 * ........................................ They are also the product of two (even three) different primes:
 * ........................................ (regardless the exponents!)
 * ........................................   i) 121 - (1+2+1)
 * ........................................  ii) 121 - (1*2*1) = 121 - (1*2*1)!
 * ........................................ iii) 121 - (1+2+1) - (1*2*1)
 * ........................................  iv) 121 - (1+2+1)^(1*2*1) = 121 - (1*2*1)^(1+2+1)
 * ........................................ If it were accidentally deleted a 1 in the 121 of (iii)
 * ........................................   v) 12 - (1+2+1) - (1*2*1)
 * .Have..a..nice..Capicua..day!!!.........  vi) 21 - (1+2+1) - (1*2*1)
 * ........................................
 *
 * 121-(1+2+1)! is prime;
 * -1*matrix(4,4,i,j,(i<=j))*([3,1,0,2]~-[2,0,1,3]~); \\ (PARI/GP)
 *
 * Finally, count the dots and the asterisks present inside this comment,,,,,,
 * subtract both counts, the result is the product of a capicua number by the sum of its digits!
 * Also the sum of the digits in such difference yields the abbreviation for the year in course :-D
*/